"Well, nobody expected it to be this way," said Bloomberg, the billionaire media mogul and former mayor of New York City. "Nobody, there's nobody that thought he had a possible shot at this. And yet he has fooled everybody. Fooled isn't quite the right word — he just surprised everybody."

Bloomberg said that even if he felt a strong urge to enter the race, he knew that the electoral system wouldn't have given him a shot at winning.

He grabbed headlines earlier this year as he considered a third-party run for the White House. He believed that there could be an opening if Trump and Bernie Sanders, a Vermont senator, secured their respective parties' nominations. Bloomberg eventually decided against a run.

On Tuesday, he said that the biggest effect he could've had in a three-way race would have been to throw the election to the House of Representatives, which likely would have selected the candidate of the party with control of the legislative body.

"So you just can't win as a third candidate," he said. We "took a look at it, and we did a lot of polling. ... [We were] not going to get a majority."

Bloomberg didn't outright endorse Clinton or Trump for the presidency. Asked to give any advice to Trump, the fellow Manhattan billionaire, who has all but sealed the GOP nomination, Bloomberg said that he's "certainly nobody to give him advice."

"Trump marches to his own drummer, it would seem," he said. "And so far, that drummer's been playing the right tune to get him this far. Can it take him to the finish line? Only history will tell."